1. Field of the Invention
The present invention is related to a mass storage device and more particularly to a mass storage device with removable storage media and methods of locating components within the mass storage device.
2. Background Description
Data storage systems administering data stored on removable storage media, such as an automated storage media (e.g., tape cartridges) and retrieval library for storing and accessing removable storage media, are well known in the art. In a typical prior art such data storage system, an automated tape library accessor or robot accessor is calibrated to locate elements such as storage cells and drive feed slots within the physical space of the system. For example, a light source/receiver or teach sensor at the accessor senses reflections from a fixed reflective fiducial mark. Tape storage cells are located at known positions relative to the fiducial mark or to a specific reference on the fiducial mark, e.g., a corner or an edge. So, by finding certain edges of the fiducial mark, precise coordinates of the associated cells can be calculated and used for later access.
Initially, the accessor locates the fiducial by moving the teach sensor to an expected fiducial location, which is where the accessor should find the fiducial. In actual practice, however, and especially with the passage of time since the most recent alignment, the accessor seldom finds the fiducial mark at the expected location. Consequently, the accessor usually conducts a search, following a selected search pattern, often in two passes, to locate the fiducial mark. Once the accessor locates the fiducial, the accessor can align to the reference edges. In some instances as the system ages, misalignment may cause the accessor to overshoot the fiducial mark by margins that increase with age. When this occurs, the accessor may be unable to locate the correct fiducial, instead finding another fiducial mark or mistaking a tape cartridge label for the fiducial mark.
Thus, there is a need to insure that an automated tape library accessor find all fiducial marks with certainty within a tape library system.